Endcap for use with an endoscope

ABSTRACT

A guide system for use with an endoscope, and a method of use is disclosed. The guide system can include a track, in the form of a rail, and a mating member for engaging the rail. The guide system can also include an accessory, such as an accessory guide tube through which a medical instrument can be carried external of the endoscope. An end cap can be provided to support the track relative to the distal end of the endoscope.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This applications cross references the following patentapplications filed on the same date: END 5120, “Method of GuidingMedical Devices”, and END 5119, “Medical Apparatus for use with anEndoscope”.

FIELD OF THE INVENTION

[0002] The present invention relates to medical devices, and morespecifically to a medical device for use in placement of one or moremedical instruments or accessories within a patient's body.

BACKGROUND

[0003] Minimally invasive procedures are desirable because suchprocedures can reduce pain and provide relatively quick recovery timesas compared with conventional open medical procedures. Many minimallyinvasive procedures are performed with an endoscope (including withoutlimitation laparoscopes). Such procedures permit a physician toposition, manipulate, and view medical instruments and accessoriesinside the patient through a small access opening in the patient's body.Laparoscopy is a term used to describe such an “endosurgical” approachusing an endoscope (often a rigid laparoscope). In this type ofprocedure, accessory devices are often inserted into a patient throughtrocars placed through the body wall.

[0004] Still less invasive treatments include those that are performedthrough insertion of an endoscope through a natural body orifice to atreatment site. Examples of this approach include, but are not limitedto, cystoscopy, hysteroscopy, esophagogastroduodenoscopy, andcolonoscopy. Many of these procedures employ the use of a flexibleendoscope during the procedure. Flexible endoscopes often have aflexible, steerable section near the distal end that can be controlledby the user by utilizing controls at the proximal end.

[0005] Some flexible endoscopes are relatively small (1 mm to 3 mm indiameter), and may have no integral accessory channel (also calledbiopsy channels or working channels). Other flexible endoscopes,including gastroscopes and colonoscopes, have integral working channelshaving a diameter of about 2.0 to 3.5 mm for the purpose of introducingand removing medical devices and other accessory devices to performdiagnosis or therapy within the patient. As a result, the accessorydevices used by a physician can be limited in size by the diameter ofthe accessory channel of the scope used. Additionally, the physician maybe limited to a single accessory device when using the standardendoscope having one working channel.

[0006] Certain specialized endoscopes are available, such as largeworking channel endoscopes having a working channel of 5 mm in diameter,which can be used to pass relatively large accessories, or to providecapability to suction large blood clots. Other specialized endoscopesinclude those having two working channels. One disadvantages of suchlarge diameter/multiple working channel endoscopes can be that suchdevices can be relatively expensive. Further, such largediameter/multiple working channel endoscopes can have an outer diameterthat makes the endoscope relatively stiff, or otherwise difficult tointubate.

[0007] Various references describe methods or systems that discloseexternal configurations related to an endoscope, such as for example:U.S. Pat. No. 5,025,778, Silverstein; U.S. Pat. No. 4,947,827, Opie; US2002/107530 published Aug. 8, 2002 in the name of Sauer; U.S. Pat. No.6,352,503, Matsui. One disadvantage of known systems is the potentialfor the distal end of a device used externally of an endoscope to movein a relatively uncontrolled manner, causing the accessory to lackprecision or the ability to be maintained within a desired field of viewof the imaging capability of the endoscope.

[0008] WO 00/48506 published Aug. 24, 2000 in the name of Herrmanndiscloses a deformable endoscope with at least one supplementary device.The unit comprising the endoscope and the supplementary device is saidto have a non-round cross-section. Such a non-circular endoscope may bedisadvantageous from the point of view of cost, complexity, or ease incleaning/sterilization. For instance, a standard endoscope with asmooth, substantially-circular cross section can be relatively easy tosanitize and clean.

[0009] WO 00/48506 published Aug. 24, 2000 in the name of Kortenbach,discloses methods and devices for delivering a medical instrument overthe exterior of an endoscope to allow the use of instruments too largeto fit through the lumena of the endoscope. Kortenbach discloses acollar for use with an endoscope, resilient straps, a flexible sheathhaving a reclosable seam, flexible polymer extrusions, and a floppytangential sheath defining a lumen having an irregular (collapsible)cross section. Kortenbach also discloses a track with an inverted Tconfiguration.

SUMMARY OF THE INVENTION

[0010] Applicants' have recognized the need for a medical apparatus,such as a disposable medical apparatus, which can be used in connectionwith an endoscope to place and/or guide accessory medical instrumentswithin the body of a patient, without requiring expensive modificationsto the endoscope. Applicants' have also recognized the need for amedical apparatus which can be used in connection with an endoscope toplace accessory medical instrument within the body of a patient, withoutsubstantially altering the flexibility of the endoscope.

[0011] In one embodiment, the present invention provides an end capadapted to fit on the distal end of an endoscope, wherein the end capcomprises a through bore for receiving the distal end of the endoscope,and wherein the end cap has an outer surface adapted to guide a medicalinstrument. The end cap outer surface can be adapted to guide a medicalinstrument relative to an axis of the endoscope.

[0012] In one embodiment, the endcap outer surface comprises an inclinedsurface feature, such as a slot. The surface feature can be useful inguiding a medical instrument relative to an axis of the endoscope. Aflexible track can be provided, the flexible track extending proximallyfrom the endcap. The track can have a length of at least 50 cm, moreparticularly at least about 100 cm.

[0013] The endcap can be used in association with a guide systemcomprising a flexible track. The flexible track can fit into or beotherwise attached to the surface feature on the outside surface of theendcap. In one embodiment, the flexible track can extend intermediate aproximal handle and the endcap. The proximal handle can be used tosupport the track relative to the proximal portion of the endoscopeoutside the patient, while the endcap can be used to support the trackrelative to the distal end of the endoscope inside the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a cross-section view of a guide system according to oneembodiment of the present invention and showing an accessory 50 attachedto a mating member 40, with mating member 40 slidably engaging a rail30, and with rail 30 attached to a flexible attachment flange 25.

[0015]FIG. 2A is an isometric illustration of an accessory guide 50 anda mating member 40 according to an embodiment of the present invention.

[0016]FIG. 2B is an isometric illustration of a rail 30, flange 25, anda thin walled tube or sheath 27, with flange 25 attached to thin walledtube 27 and flange 25 extending generally radially from thin walled tube27.

[0017]FIG. 2C is a cross-sectional illustration showing accessory guide50 and flange 25 supported in sliding engagement with rail 30, such thataccessory guide 50 is spaced radially from thin wall tube or sheath 27.

[0018]FIG. 3A is a front view of an end cap 55 showing several featuresincluding a gripping surface 58 and a guide notch 63.

[0019]FIG. 3B is a cross section taken at line 3-3 of FIG. 3A showinginclination angle 65.

[0020]FIG. 4A is an isometric view of the distal end of a guide system20 in use with an endoscope 100, and showing field of view 110.

[0021]FIG. 4B is an isometric view of the proximal end of the guidesystem 20 in combination with an endoscope 100.

[0022]FIG. 5A-E show cross section views of various embodiments of arail 30 and a mating member 40.

[0023]FIG. 6 is a cross section view of an embodiment of the guidesystem 20 according to the present invention showing an attachment meansto connect guide system 20 to endoscope 100 through a sheath 80 with aninverted rail 30 disposed within the sheath 80.

[0024]FIG. 7 is a side view endoscope 100 in a retroflexed curvature,showing rail 30 with a curvature radius R2 different from radius R1 ofendoscope 100, and also showing the rail 30 and flange 25 folding or“warping” out of the plane of curvature of the endoscope, and such thatrail 30 moves circumferentially relative to endoscope 100.

[0025]FIG. 8 is a side view of rail 30 associated with an end cap 55 todirect a non-articulating medical instrument 168 extending from anaccessory 50 (in the form of a guide tube 50) into field of view 110 ata convergence point 115 with an instrument 68 extending from an integralchannel 93 of endoscope 100.

[0026]FIG. 9 shows a side view of an embodiment of guide system 20without end cap 55 being used with an articulating accessory 71 used toposition the distal end of accessory 71 into the field of view 110.

[0027]FIG. 10 is an isometric view showing one technique that may beused to direct instrument 168 from accessory 50 into field of view 110with a snare 73 extending from integral channel 93.

[0028]FIG. 11A-C are front views of end cap 55 placed at differentorientations on endoscope 100 in order to change the relative positionof accessory 50 with respect to integral channel 93 and lens 107 (andlocation of convergence point 115).

[0029]FIGS. 12A and 12B are isometric views of one method of using guidesystem 20 with accessory 50 and instrument 68 to remove a tissue 130without removing endoscope 100 from its position within the patient.

[0030]FIG. 13 shows a cross section view of a proximal end of handle 60attached to endoscope 100.

[0031]FIG. 14 is an isometric view of a distal end of endoscope 100 withrail 30 wrapped around endoscope 100 in a helical arrangement.

[0032]FIG. 15 is a cross section view showing a proximal end ofendoscope 100 with an arrangement of a second mating member 120 beingused to disengage a first device 118 from rail 30.

[0033]FIG. 16 is a side view showing a short, relatively straight andrelatively rigid device 125 supported on and slid along rail 30 along asection of endoscope 100 curved (such as by retroflexing) to have aradius R3.

DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention is a guide system to facilitateintroduction of medical accessories into the body of a patient. By wayof example, the present invention is illustrated and described forapplication in flexible endoscopy in a colon of a human patient.However, the present invention is applicable for use in other medicalsettings, including but not limited to, rigid endoscopy, laparoscopy,cystoscopy, hysteroscopy, esophagogastroduodenoscopy, sigmoidoscopy,proctoscopy, or enteroscopy in which the body lumens of humans or othermammals are accessed.

[0035]FIG. 1 shows a cross section of one embodiment of a guide system20 according to one embodiment of the present invention. In FIG. 1,guide system 20 is illustrated as generally comprising a track in theform of guide rail 30, a mating member 40, and an accessory 50. In theembodiment shown in FIG. 1, accessory 50 can be in the form of aflexible tubular guide for receiving and guiding a medical instrumentalongside an endoscope. Guide system 20 can be used to facilitateintroduction of accessory 50 into the body of a patient by providing ameans to slide accessory 50 along the length of another medicalinstrument, such as an endoscope, in a controlled manner. Rail 30 may beflexibly supported in spaced relationship from the outer surface of theendoscope by a flexible web in the form of flange 25. Flange 25 can havea thickness t of between about 0.005 inch and about 0.030 inch, and aheight h of between about 0.020 inch and 1.0 inch. In one embodiment,height h can be between about 0.080 inch and about 0.200 inch, such asin applications related to the use of colonoscopes in colonoscopy.Flange 25 can be formed of a flexible material, such as a flexibleplastic material. One suitable material from which flange 25 can beformed is a thermoplastic elastomer, such as a material designatedcommercially as Telcar 1025-75 (available from Teknor-Apex, Pawtucket,R.I.). Height h provides standoff of accessory 50 from the outsidesurface of the endoscope. Height h can be selected to be greater than orequal to about one half the outer diameter of the endoscope with whichthe guide system 20 is used. Without being limited by theory, such aheight h may provide the advantage that upon bending/flexing of theendoscope 100, such a height h of the flange 25 can permit the rail 30to move into approximate alignment with the neutral axis of bending ofthe endoscope, so that rail 30 does not signicantly increase the bendingstiffness of the endoscope 100.

[0036] Mating member 40 is operatively coupled to rail 30 throughinterlocking contours. A first contour 140 of mating member 40 can havea substantially matching shape to a second contour 132 of rail 30, sothat mating member 40 slides along rail 30. There is a nominal clearancedistance between the mating surfaces of mating member 40 and rail 30, sothat no binding or pinching occurs when sliding one relative to theother. A nominal clearance of 0.005″ may be provided to allow sliding ofmating member 40 along rail 30 like a drawer in a drawer slide.

[0037] One or both of rail 30 and mating member 40 can be made from aflexible, low friction (“slippery”), plastic material, such aspolyethylene, Teflon, or polypropylene to provide a low coefficient offriction between the members as they slide relative to one another.Because the length (as measured perpendicular to the plane of FIG. 1) ofguide system 20 is much longer than the width (measured parallel to ahorizontal line in the plane of FIG. 1) of the cross section, variouscomponents such as rail 30, mating member 40, attachment flange 25, oraccessory 50 may be made with an extrusion process, but such a processis not required. Additionally, rail 30 and flange 25 can be formed as aunitary piece, such as by extrusion. Likewise, mating member 40 andaccessory 50 can be formed as a unitary piece, or joined by any suitableattachment method. In FIG. 1, flange 25 can include an attachment base24. Attachment base 24 can provide releasable attachment of the flange25 to the outer surface of an endoscope. For instance, attachment base24 can include an adhesive layer on a bottom surface 23, by which flange25 can be attached to an endoscope. Flange 25 may also be secured toendoscope with adhesive sprays or tapes, Velcro-like attachmentmaterials, non-adhesive silicone tape, with segments of heat shrinktubing, or other suitable attachment means. Such attachments enable rail30 to be attached to numerous sizes of standard endoscope, allowingguide system 20 to be compatible with standard equipment already ownedby a user.

[0038]FIGS. 2A-2C illustrate another embodiment of a guide system 20 ofthe present invention. FIG. 2A is an isometric view of the accessory 50and mating member 40 of a guide system 20. FIG. 2B is an isometric viewof the rail 30 and attachment flange 25 associated with a thin wall tube27. FIG. 2C is cross-sectional view of an assembled guide system 20,including accessory guide 50, mating member 40, rail 30, flange 25, andthin walled tube 27, which can be in the form of a flexible sheath.

[0039] In FIG. 2B and FIG. 2C, the attachment flange 25 can be attachedto, or be integrally formed with (such as by extrusion) the thin walltube 27. Thin wall tube 27 is flexible, and can be sized to slide overan endoscope. The guide system 20 of the present invention can have ancontinuous, uninterrupted length which is substantially the same as theinsertion length (length that is meant to go inside the patient) of anendoscope 100. Alternatively, the guide system can have an overalllength that is greater than the insertion length of the endoscope 100.In one embodiment, the thin walled tube 27, the flange 25, and the rail30 can have a continuous, uninterrupted length of at least about 50centimeters, more particularly at least about 100 cm, and still moreparticularly at least about 160 cm, such as for work associated with acolonoscope and colonoscopy.

[0040] The inner diameter of the thin wall tube 27 can be sized to beslightly greater than the outer diameter of the endoscope 100. Endoscope100, disposed in the thin wall tube 27, can rotate relative to the tube27, such as when endoscope 100 is retroflexed or otherwise bent orcurved. Such relative rotation of the tube 27 (and so flange 25 and rail30) with respect to the endoscope can assist in the rail 30 beingcapable of moving circumferentially relative to endoscope 100 and takingon a position that is approximately aligned with the neutral axis ofbending of the endoscope.

[0041] The thin walled tube 27 and attachment flange 25 shown in FIGS.2B and 2C may be made from a flexible plastic, such as thermoplasticelastomer, one example of which is Telcar 1025-75 (Teknor-Apex,Pawtucket, R.I.). The wall thickness of the thin walled tube 27 andattachment flange 25 may be about 0.0020″. Although connected toattachment flange 25, rail 30 may be made from a different material,such as polypropylene, which may be used for providing ease of sliding.One suitable polypropylene is Pro-fax 7823 (Basell, Wilmington, Del.). Acoextrusion process may be used to form an integral extruded part fromat least two different materials, such as with one embodiment of rail 30and attachment flange 25.

[0042] Likewise, similar materials and processes may be used to createaccessory 50 attached to mating member 40. For embodiments whereinaccessory 50 is in the form of a flexible guide tube, accessory 50 canbe made from thermoplastic elastomer, such as Telcar 1025-75 (availablefrom Teknor-Apex of Pawtucket, R.I.). Mating member 40 can be made froma “slippery” low friction material, such as Teflon, polyethylene, orPro-fax 7823 polypropylene (available from Basell Co. of Wilmington,Del.). Mating member 40 and accessory 50 may be formed through acoextrusion process, or alternatively, may be joined together by anyother suitable joining technique.

[0043] In use, the rail 30 can be supported on the endoscope prior toinsertion of the endoscope into the patient (such as by sliding the thinwall tube or sheath 27 and rail 30 over the endoscope prior to insertioninto the patient). Once endoscope 100 is in a position within the body,mating member 40 can be engaged with rail 30, and the mating member 40and the accessory 50 can then advanced along the length of the endoscopeby sliding engagement with rail 30, so that accessory 50 is positionedin or near a field of view 110 (see FIG. 4A) to perform treatment ordiagnosis (such as by advancing a medical instrument through accessory50).

[0044] In the embodiments shown in FIGS. 1 and 2A-2C, the guide system20 couples rail 30 to endoscope during a procedure, but does notsubstantially stiffen the endoscope, and is removable after theprocedure without altering or disassembling endoscope. The embodimentsshown in FIG. 1 and FIGS. 2A-C permit the rail and associated accessoryguide 50 to be attached to various sizes of standard endoscopes,allowing guide system 20 to be compatible with standard endoscopesalready owned by the user, and avoiding the need to purchase additionalnew specialized capital equipment. Rail 30 can be disposable so thatafter a single patient use, it can be removed from the Endoscope anddiscarded with other medical waste. Disposability avoids therequirements for cleaning, which could be difficult and time consumingconsidering the shape of rail 30 which may incorporate a long narrowgroove. Mating member 40 and accessory 50 may also be disposable.

[0045] In the embodiments shown, the guide system 20 couples rail 30 andthe associated accessory 50 to the endoscope such that flexibility andmaneuverability of the endoscope is maintained. By way of example, butwithout limitation, the guide system of the present invention can beused with a colonoscope without appreciably changing the stiffness ofthe colonoscope and without appreciably changing the colonoscopesbending axis, due at least in part to the ability of the rail 30 to takeon a curved path different from that of the curved endoscope, and theability of rail 30 to take on a position that is approximately alignedwith the neutral axis of bending of the endoscope. Accordingly, thepresent invention obviates the need to employ a specialized endoscopehaving a non-circular cross section, or a cross section that isotherwise modified, such as to provide preferential bending or toaccommodate the use of accessories along the side of the endoscope.

[0046] Referring to FIGS. 2A-2C, guide system 20 can have a matingmember 40 and a rail 30 either or both of which is substantially thesame length as, or longer than the endoscope with which they are used.Such a configuration allows a user to slide accessory 50 (and anyinstruments inserted through accessory 50) into a patient's body withoutrelying upon axial stiffness of accessory 50 (or the axial stiffness ofthe instrument inserted through accessory guide 50). Without beinglimited by theory, it is believed that mating member 40 and accessoryguide 50 can be advanced along rail 30, even though both are flexible,due at least in part to the close clearance between rail 30 and matingmember 40 and the continuous, uninterrupted nature of the track providedby rail 30. The embodiments shown permit the insertion of a softflexible accessory 50, a short accessory 50 that may not inherentlypossess the rigidity to push it along the side of endoscope 100, or theinsertion of a short rigid segment.

[0047] Guide system 20 also allows for introduction of a short, rigiddevice 125, as shown in FIG. 16. For example, a commercially availableprobe such as the BRAVO™ brand pH Monitoring System available fromMedtronics of Minneapolis, Minn. has a relatively short (approx 25 mm),relatively rigid segment. The pH monitoring system is a wireless capsulewhich is attached to the wall of the esophagus for approximately 48hours, during which data is transmitted to a remote (external topatient) receiver. The guide system of the present invention can be usedto deploy the pH monitoring capsule, such as by pushing the capsulethrough the accessory 50 to the location at which the capsule is to beattached, or by attaching the capsule to the mating member 40 andpushing the capsule by advancing mating member 40 along the length ofthe endoscope. Alternatively, the rail 30 can have a cross-section thatis sized and shaped to permit the device to slide axially along thelength of rail 30, while preventing the device from disengaging from therail.

[0048] Flexible flange 25 provides the advantage that a relatively rigiddevice, (such as for example a generally straight, relatively rigiddevice) can be pushed by sliding along rail 30, even as the flexibleendoscope is retroflexed or otherwise curved. The flexibility of theguide system 20 of the present invention decouples bending of rail 30from bending of the endoscope, so that a relatively stiff device oraccessory, that would otherwise be difficult to slide to the distal endof the endoscope, can be slid along the curved endoscope. FIG. 16illustrates schematically a relatively rigid device 125 being advancedon rail 30 around a curved segement of endoscope 100.

[0049] In another embodiment, accessory 50 can be a device having alength shorter than that of endoscope 100, and not form a workingchannel. For example, the accessory 50 could be in the form of ahemostatic gauze pad. The gauze pad could be attached to the distal endof the mating member 40, such as by suture, adhesive, staples, or aclip. The gauze could then be used to treat a bleeding site, after whichthe gauze pad could be pulled from the body by pulling mating member 40backward (proximally) along the rail 30. The present invention enablesone to push a member that is relatively short and/or has low axialstiffness. The guide system 20 of the present invention allowsadvancement of such devices into a patient at least in part becausemating member 40 can provide the axial support and the length needed tomove such a device into a patient.

[0050] Embodiments of the guide system 20 of the present inventionhaving a mating member 40 with a length that is greater than orsubstantially equal to the length of rail 30 and the insertion length ofthe endoscope provide an advantage over endoscopic systems using aengaging member that is not substantially the same length as a track. Insuch endoscopic systems, a medical instrument to which the engagingmember is attached will generally require sufficient axial rigidity toenable pushing of the medical device along the endoscope. Additionally,such endoscopic systems can require a block or “stop” at a distal end ofa surface track so that an engaging member is not advanced off the endof the track. In contrast, the embodiments of the guide system 20 of thepresent invention having a mating member 40 with a length greater thanor substantially equal to that of the rail 30 and the insertion lengthof the endoscope do not require such a block feature, and provide theadvantage that accessory 50 can be advanced beyond the end of theendoscope into a field of view of the endoscope, and then retracted.

[0051]FIGS. 3A and 3B and FIGS. 4A and 4B illustrate an end cap 55according to one embodiment of the present invention. FIG. 3A is an endview of the end cap 55, and FIG. 3B is a cross-sectional view takenalong section line 3-3 in FIG. 3A. End cap 55 can be a component of aguide system 20 according to one embodiment of the present invention, oralternatively, end cap 55 can be a separate, stand alone accessory. Endcap 55 can be configured to be releasably attachable to the distal endof an endoscope 100. By releasably attachable it is meant that end cap55 can be repeatedly attached to, and removed from, the endscope withoutdamaging either the end cap 55 or endoscope. End caps 55 can be providedin various sizes to fit onto the ends of various diameter endoscopes.End cap 55 can receive the distal end of rail 30, and can help controland guide accessory 50 in a field of view 110 (see FIG. 4A) of endoscope100.

[0052]FIG. 3B shows a cross-section of the junction of the thin wallflexible tube 27, flexible attachment flange 25, and rail 30 to end cap55. The junction may be accomplished by adhesive joining or any othersuitable joining method. A distal portion of the rail 30 can extend andbe held by the notch 63 so that the mating member 40 can slide along theoutside surface of end cap 55 in a continuous, non-interrupted path.

[0053] End Cap 55 can include a relatively rigid external body, and arelatively soft internal insert 56 with a through bore 57. The insertcan include a gripping surface 58. Insert 56 and gripping surface 58 canbe provided for releasably attaching end cap 55 to endoscope 100, suchthat end cap 55 is pushed onto the distal end of endoscope 100 withoutthe need for special tools or assembly techniques to attach or removeend cap 55 to the end of the endoscope. The insert and gripping surface58 may be made from a sticky or tacky material such as silicone orneoprene, or may include adhesive to hold end cap 55 in place on thedistal end of the endoscope 100 Alternatively, end cap 55 can be held inplace using a snap fit, an interference fit, or any other suitableattachment means which permits end cap 55 to be releasably attached tothe distal end of an endoscope. The remainder of the body of end cap 55including the external body may be made from a biocompatible plastic,such as nylon 6/6, polycarbonate, or polyvinyl chloride (PVC).

[0054] End cap 55 can be provided with smooth rounded edges on itsexternal surface, and connects to a distal portion of endoscope 100. Theend cap 55 includes a surface feature on its external surface adapted toguide a medical instrument, such as a medical instrument advancedexternally along the endoscope (such as in an accessory guide tube 50).The surface feature can be in the form of a slot, such as guide notch63. Guide notch 63 can be shaped to receive the distal end of rail 30.The distal end of rail 30 can extend into guide notch 63 (FIG. 4A), andthe distal end of rail 30 can take on a path determined by the geometry(slope or incline) of guide notch 63, so that the distal end of matingmember 40 sliding on rail 30 can follow a path determined by thegeometry of guide notch 63. In the embodiment shown, the guide notch 63is inclined radially inward from the proximal end of the guide notch tothe distal end of the guide notch.

[0055] In the embodiment shown, guide notch 63 is inclined with respectto the axis of through bore 57 (and so inclined with respect to thelongitudinal axis of the endoscope to which end cap 55 is attached). Theangle at which guide notch 63 is inclined is indicated by referencenumeral 65 to direct accessory 50 into field of view 110. This featureof end cap 55 may be useful to provide convergence of accessory 50inserted using guide system 20 to an instrument 68 inserted through anintegral channel 93 (FIG. 6) of endoscope 100. Depending on the value ofangle 65, location of a convergence point 115 (FIG. 8) may change. Inone embodiment, angle 65 may be at least about 5 degrees, and moreparticularly at least about 10 degrees. In one embodiment, the angle 65can have a value between about 10 degrees and about 30 degrees.

[0056] In an alternative embodiment to end cap 55, the flange 25 can betapered, such as by being tapered radially inwardly (e.g. with theflange height h being reduced at the distal end of the flange 25), sothat rail 30 on flange 25 is directed radially inwardly at the distalend of the guide system 20 to guide the accessory 50 both axially andradially inwardly at the distal end of the endoscope 100.

[0057]FIGS. 4A and 4B illustrate distal and proximal ends of guidesystem 20 attached to endoscope 100. FIG. 4A shows a distal end of guidesystem 20 with end cap 55, attachment flange 25, thin wall tubularsheath 27, mating member 40, rail 30, and endoscope 100 (extendingthrough bore 57 of end cap 55). In the embodiment shown, accessory 50 isin the form of an external working channel 52. Working channel 52 canreceive and guide a variety of medical instruments from a point outsidethe patient to a position distal of the distal end of the endoscopewithin the patient.

[0058] As shown in FIG. 4A, the leading (distal) end of mating member 40can have a tapered or an inclined edge 41 shaped to allow atraumaticpassage along endoscope 100 inside a patient's body. The interfacebetween rail 30 and mating member 40 can be located to avoid pinchingtissue as the mating member 40 slides in rail 30, such as by locatingthe interface below an outer surface 144 of rail 30. A smooth coveringor a tapered nose on the leading edge of accessory 50 can be employed.

[0059]FIG. 4B shows one embodiment of a proximal portion of guide system20, including flexible tubular sheath 27, attachment flange 25, rail 30,and a hollow handle 60. Handle 60 includes a through bore for receivingan endoscope such that the endoscope can pass through handle 60. Handle60 may be constructed of a soft tacky material, such as neoprene orsilicone, and may include a slot 36 formed in handle 60 for receivingthe proximal end of rail 30. A funnel feature 37 at the proximal end ofslot 36 can be employed to facilitate insertion of mating member 40 intorail 30. Handle 60 may be designed to slide over the distal end of anendoscope 100, and can have an internal conical shaped surface to fitagainst a proximal portion of endoscope 100, near an introductory port105 integral to endoscope 100, as shown in FIG. 4B. Introductory port105 of endoscope 100 receives medical instruments, such as medicalinstrument 68 shown in FIG. 8. The handle 60 can be permantly fixed tothe proximal end of thin wall flexible tube/sheath 27, or alternatively,can be releasably joined to the thin wall tube/sheath 27.

[0060]FIG. 13 shows a cross section of the junction of the thin walledtube 27, rail 30, and attachment flange 25 to the handle 60. Theconnection of the tube 27, rail 30, and flange 25 to handle 60 can bepermanent, such by use of adhesive. The subassembly comprising thehandle 60, thin walled tube 27, rail 30, flange 25, and end cap 55 canbe disposable, and can releasably engage the endoscope at one or morelocations. For instance, end cap 55 can releasably engage the endoscope100 at a distal end of the endoscope 100, and handle 60 can releasablyengage the endoscope 100 at a proximal portion of the endoscope 100, asshown in FIG. 13. In FIG. 13, handle 60 can have an inwardly facingconical surface that engages an outwardly facing conical surface onendoscope 100.

[0061]FIG. 5A-5D show illustrative, non-limiting embodiments of crosssectional shapes of rail 30 and mating member 40 that allow slidingengagement of rail 30 and mating member 40. It will be understood thatrail 30 and mating member 40 may take on various shapes andconfigurations, such that mating member 40 interlocks with the shape ofrail 30 to allow sliding of mating member 40 along rail 30. As viewed incross section, rail 30 can have opposing arms 31 which maintainengagement of mating member 40 with rail 30. Arms 31, together with thebody of rail 30, can define a rail cavity 33 in which the mating member40 can slide. If desired, arms 31 can be provided with a desired levelof resilience, such as by material choice or dimensioning, so thatmating member 40 can be caused to disengage from rail 30 (e.g. by“unzipping” from rail 30), such as if mating member 40 is urged radiallyoutwardly from rail cavity 33. In an alternate embodiment, not shown, awire may be employed as a rail 30 to provide a path along endoscope 100.Such a wire path may be attached at a distal and proximal end ofendoscope 100, and provide a low-profile guide for accessory 50 tofollow along endoscope 100.

[0062] The embodiment shown in FIG. 5D incorporates accessory 50 (in theform of a circular working channel) within mating member 40. Thisembodiment could enable the passage of accessories within a lumen ofmating member 40 that slides inside rail 30. For example, rail 30 mayhave a substantially triangular recessed cross section that interlockswith mating member 40 having an outer contour of a triangular shape; anda medical device can slide within a lumen 42 located within matingmember 40. This particular embodiment may be suitable for atraumaticpassage of mating member 40 along rail 30, and when passing standardsize accessories with guide system 20.

[0063] In yet another embodiment, mating member 40 can be sized andshaped to fit within rail cavity 33, and not extend above rail 30. Inyet another embodiment, as an alternative to (or variation in) thecombination of mating member 40 and accessory 50, a guide wire or guidetube having a generally circular cross-section could be disposed in railcavity 33 for sliding engagement with rail 30. The guide wire or guidetube could have a diameter sized, relative to the size of rail cavity 33and rail arms 31, such that the guide wire or guide tube can slide inrail cavity 33, while being maintained from disengaging from rail cavity33 by rail arms 31.

[0064]FIG. 6 illustrates an alternate embodiment of attachment flange 25to those shown in FIG. 1 and FIG. 2 for connecting rail 30 to endoscope100. A sheath 80 surrounds endoscope 100 and rail 30. Rail 30 can bejoined to an inner surface of sheath 80. Such an embodiment allowspassage of mating member 40 and accessory 50 within sheath 80, providingfor atraumatic passage along the tissue surface.

[0065]FIG. 7 shows a side view of rail 30 attached to endoscope 100 withone embodiment of attachment flange 25, showing how endoscope 100 andrail 30 are able to take on different curvatures, including differentcurved paths in different planes. The guide system 20 of the presentinvention provides support of the rail with respect to the endoscope 100in a manner that decouples bending of rail 30 and flange 25 from bendingof endoscope 100. Accordingly, guide system 20 does not prevent flexingof the endoscope 100. Commercially available flexible endoscopes 100have the ability to retroflex (bend back to look upon itself) at itsdistal end. FIG. 7 illustrates this retroflex ability, and how rail 30with attachment flange 25 is able to take on a path and radius ofcurvature that is different from the path and radius of curvature of theendoscope. Rail 30 can take on a radius of curvature that is some places(along the length of the endoscope 100) greater than, and in some placesless than, the corresponding radius of curvature of the endoscope 100.Without being limited by theory, it is believed that the flexibility ofthe flange 25 and rail 30 permit the flange 25 and rail 30 to deform outof the plane of curvature of the endoscope to take on a path thatreduces the elastic strain that would otherwise be present in the flange25 and rail 30. In particular, the flexible flange 25 can permit therail 30 to move into general or approximate alignment with the neutralaxis of bending of the endoscope. Accordingly, the rail 30 is not fixedin an o'clock position relative to the endoscope that requires the rail30 to be subject to tension or compression upon bending of the endoscope(as could be the case if the rail 30 where fixed at a certaincircumferential position with respect to the cross section of theendoscope). This arrangement permits the operator to retroflex theendoscope 100, and therefore allows a user to use a normal technique tomaneuver the endoscope 100 through the lumen.

[0066] By way of example, and without being limited by theory, one mayconsider bending of endoscope 100 with respect to bending a beam. Inbeam bending, there is a neutral axis (generally in the center of thebeam for symmetric beam cross sections), with one beam surface being incompression, the opposite surface being in tension. A rail supported onan endoscope in such a manner that the rail is subject to tensile stressor compressive stresses upon bending of the endoscope may impede bendingof endoscope 100 because of the rail's resistance to tension and/orcompression.

[0067] The illustration in FIG. 7 shows how a flexible attachment flange25 can minimize the affect of rail 30 on endoscope 100 bending. Theheight of attachment flange 25 effectively tethers rail 30 to endoscope100, but allows rail 30 to find a path of different curvature and/ormove circumferentially with respect to the endoscope. In compression,attachment flange 25 permits rail 30 pleat or otherwise deform (such asin a wavy fashion), minimizing the effect on endoscope 100 bending. Inembodiments including a flexible thin wall tube/sheath 27, thedecoupling of bending of the rail from bending of the endoscope can befurther enhanced due to the ability to accommodate circumferentialmovement of the tube or sheath 27 with respect to the endoscope.

[0068]FIG. 8 illustrates how end cap 55 may be used to hold a distal endof rail 30 to endoscope 100 and present accessory 50 or instrument 168into field of view 110. Guide system 20 provides a convergence point 115for a medical instrument 168 extending from an accessory 50 (in the formof an external guide channel in FIG. 8) and an instrument 68 extendingfrom an integral working channel 93 of endoscope 100. This featureallows accessory 50 and instrument 168 to be used in conjunction withinstrument 68 to perform multiple-handed therapy or diagnosis, such thatinstrument 168 and instrument 68 are not required to have separatearticulation capabilities. In contrast, an endoscope configuration thatdoes not provide the guided convergence (such as at point 115) of thepresent invention would typically require one or more instruments tohave an articulation feature or other mechanism for providing curvatureat the instrument's distal end if it is desired to have one instrumentcooperate with another in the endoscope's field of view.

[0069] Referring to FIG. 9, if the guided convergence of end cap 55 isnot provided, cooperation of multiple instruments (such as atconvergence point 115) in field of view 110 would require one ofinstruments (such as instrument 77 in FIG. 9) to have a built inarticulation capability. End cap 55 with angle 65 allows a user to usestandard, non-articulating, accessories or instruments to achieve newtherapies or diagnoses.

[0070]FIG. 10 shows a guidance system 20 of the present invention andillustrates a method of articulating an instrument (such as instrument168 extending from accessory 50) with a snare 73 extending from integralchannel 93 of endoscope 100. The snare 73 can be in the form of a loopedwire, and can be advanced from channel 93 to meet an instrument 168extending from accessory 50. Once the instrument 168 extends through theloop in snare 73, the curvature of instrument 168 can be increased byadvancing instrument 168 from accessory 50, and/or by retracting snare73 in channel 93. Accordingly, the instrument 168 can be positioned at adesired site (such as a tissue site on the wall of the GI tract).

[0071] FIGS. 11A-C illustrate an additional advantage of use of the endcap 55 of the present invention. FIGS. 11A-C illustrate the end cap 55positioned at various o'clock positions on the distal end of endoscope100. End cap 55 can be positioned on the endoscope 100 so that accessory50 is located in a desired o'clock position with respect to one or morefeatures of the endoscope, such as integral working channel 93 oroptics/viewing lens 107. For instance, in some applications it may bedesirable to have the integral channel 93 positioned at a certaindistance with respect to accessory 50 to perform a procedure, while inother applications it may be desireable to position the viewing lens 107at a particular position relative to accessory 50 to obtain a desiredfield of view.

[0072]FIGS. 12A and 12B illustrate an alternative embodiment in whichguide system 20 comprises an adhesive-backed elastically extensiblerail, the elastically extensible rail designated by numeral 32 in FIGS.12A and 12B. Elastically extensible rail 32 can be formed of a suitableelastically extensible material, so that rail 32 elongates in tensionand folds, buckles, or otherwise bends in compression when endoscope isbent or otherwise flexed during use. Rail 32 accommodates bending of theendoscope without substantially altering the bending stiffness of theendoscope. A suitable material for rail 32 is Santoprene ThermoplasticRubber (Advanced Elastomer Systems, Akron, Ohio), and a suitableflexible adhesive for attaching rail 30 directly to the outside surfaceof the endoscope is Super 77 Spray adhesive (3M, St. Paul, Minn.). Suchan embodiment allows rail 32 to change in length or otherwise deform asendoscope 100 is bent, and may be used in embodiments where a flexibleflange 25 is not provided.

[0073] In FIGS. 12A and 12B, a tissue mass is shown being captured andsevered by a snare 73 extending from a working channel of the endoscope,and grasped by an instrument 168, such as a flexible forceps. Theflexible forceps extends through accessory 50 (which is in the form of aflexible guide tube in FIG. 12A), and the flexible forceps can then beused to withdraw the severed tissue mass from the gastrointestinal tractthrough the accessory 50.

[0074]FIGS. 12A and 12B show one of numerous treatment methods that maybe enabled by guide system 20. Removal of multiple biopsies of a tissue130, such as large polyps currently requires removal of endoscope 100with the tissue sample 130. This can be time consuming, especially ifthe physician needs to re-introduce the endoscope 100 through a tortuouscolon. FIGS. 12A and 12B illustrates how guide system 20 would provide away to remove such an incised polyp without removing the endoscope 100.

[0075]FIG. 13 is a cross section view of a proximal end of guide system20, including a cross section of the attachment of handle 60 toendoscope 100. One component of handle 60 is a guide bar 76 that can beprovided (such as by attachment to handle 60) to prevent unintentionaldisengagement of mating member 40 from rail 30. Mating member 40 can befed between the guide bar 76 and the body of handle 60 into funnelfeature 37. Guide bar 76 can prevent mating member 40 from beinginadvertently “peeled” out of or “unzipped” from rail 30 at its proximalend.

[0076] In use, a distal end of endoscope 100 can be inserted through thebore in handle 60, through sheath 27, and into the bore of end cap 55.Releasable connections of handle 60 and end cap 55 to endoscope 100 maythen be made to hold guide system 20 in place during a procedure. Theinner diameter of sheath 27 is preferably sized to allow insertion ofendoscope 100 without the need for a lubricant between endoscope 100 andsheath 27. To achieve this, a nominal clearance of at least about 0.040″may be provided between the diameter of endoscope 100 and the innerdiameter of sheath 27.

[0077] The endoscope 100 with rail 30 can then inserted into the body ofa patient. When desired, the physician can then introduce mating member40 into a funnel feature 37 and slide accessory 50 with mating member 40along rail 30 into the body of a patient. Accessory 50 may be a workingchannel, through which instrument 168 may be introduced. The physiciancan then extend instrument 168 into a field of view 110 to perform aprocedure.

[0078] While accessory 50 has been described primarily as an additionalworking channel, it will be understood that accessory 50 can take otherforms. Other devices which can be provided as suitable accessoriesinclude, but are not limited to, a biopsy forceps, an articulatinginstrument, a surgical scissor, a device adapted for sewing or staplingtissue, a guidewire, a device adapted for liquid or gas injection, or atissue ablation system. For instance, various medical instruments couldbe could be modified to include a mating member configured to fit andslide in rail 30 (e.g. such as by permanently or non-permanentlyattaching a mating member 40 to the instrument). Or, alternatively, therail cavity 33 and rail arms 31 can be sized and shaped to accept aparticular medical instrument for sliding engagement in rail cavity 33.

[0079] Additionally, a plurality of endoscopes 100 can be connected toeach other using guide system 20 by attaching rail 30 to one “parent”endoscope 100, and attaching mating member 40 to a second “daughter”endoscope. Such an arrangement would allow the scopes to be connectedand slide relative to each other, providing multiple perspectives of anobject within the body of a patient.

[0080] Those skilled in the art will also recognize that a plurality ofrails 30 may be attached to endoscope 100 to provide multiple paths forinstruments to be fed along the outside of endoscope 100. The pluralityof rails 30 may be attached to a plurality of attachment flanges 25 orto a common attachment flange 25.

[0081]FIG. 14 illustrates an embodiment of a guide system 20 whereinrail 30 is wound in a generally helical fashion about an endoscope 100.For instance, the distal end of rail 30 can be joined to the distal endof an endoscope 100, the rail 30 can be wound in a helical manner and ina proximal direction along the endoscopes length, with a proximal end ofthe rail 30 being joined to a proximal portion of the endoscope. In FIG.14, the distal end of rail 30 is shown associated with an end cap 55. Inone embodiment, a guide system 20 can comprise a handle 60, an end cap55, and a rail 30 extending intermediate the handle 60 and the end cap55, in which embodiment the flange 25 and flexible tube 27 may beomitted if desired. The end cap 55 can be attached to the distal end ofthe endoscope, and the rail 30 can be wound loosely about endoscope 100(or extended in a generally linear fashion along the endoscope 100 withsufficient slack in rail 30 to allow rail 30 to accommodate bending ofthe endoscope).

[0082]FIG. 15 is a cross section view showing a proximal end of a guidesystem 20 attached to endoscope 100. One method of using guide system 20may be to introduce a first device 118 into the body of a patient byintentionally disengaging first device 118 from rail 30 with a secondmating member 120. This can be achieved by first introducing firstdevice 118 into rail 30, then disengaging a proximal end of first device118 from rail 30 (e.g by pulling the proximal end of first device 118upward in the plane of FIG. 15 to disengage the proximal end of firstdevice 118 from the rail 30), and then introducing the second matingmember 120 into sliding engagement with the rail, so that second matingmember 120 is disposed between the first device 118 and rail 30 toeffectively “unzip” first device 118 from rail 30 as second matingmember 120 is advanced distally down the length of rail 30.

[0083] For example, first device 118 may be a guidewire, a feeding tube(e.g. to be placed in the esophageal lumen to extend from the oralcavity to the stomach), a duct for conveying a liquid or gas, or anyother instrument that is meant to be positioned within a body lumen fortemporary or permanent placement. The rail 30 can be positioned withinthe body lumen, such as by being associated with an endoscope which isintroduced into the body lumen. The first device can be introduced ontorail 30 and advanced distally along the rail into a predeterminedposition within the body. A proximal end of the device 118 can then bedisengaged from the rail, as shown in FIG. 15. The second mating member120 can then be introduced under guide bar 76 and into engagement withthe rail 30, and advanced axially along the rail in a distal directionto force the device 118 out of engagement with the rail 30, therebyleaving device 118 in place in the body lumen. Advancing second matingmember 120 along the rail 30, wherein member 120 is interposed betweenrail 30 and device 118, causes the device 118 to be urged out of therail 30 and deployed in a direction generally perpendicular to the rail30. As shown in FIG. 15, member 120 can have a tapered distal end toenhance the ability of member 120 to be interposed between rail 30 anddevice 118 for urging device 118 out of engagement with rail 30.

[0084] Referring again to FIG. 16, the guide system 20 of the presentinvention can provide advancement and positioning of a relatively rigidand straight device 125 along a curved portion of an endoscope 100. InFIG. 16, the device 125 can be pushed by or carried on a mating member40. The portion of the track 30 on which device 125 is positioned can berelatively straight, in comparison with the corresponding portion of theendoscope which is curved.

[0085] While various embodiments of the present invention have beendisclosed, it will be obvious to those skilled in the art that suchembodiments are provided by way of example only. The present inventionmay be provided in kit form with other medical devices, includingmedical devices useful in the working channel of an endoscope, or withan endoscope. The kit elements can be pre-sterilized and packaged in asealed container or envelope to prevent contamination. The presentinvention may be provided as a single use disposable device, oralternatively, may be constructed for multiple uses. Further, eachelement or component of the present invention may be alternativelydescribed as a means for performing the function or functions performedby the element or component. Numerous variations, changes, andsubstitutions will now occur to those skilled in the art withoutdeparting from the invention. Accordingly, it is intended that theinvention be limited only by the spirit and scope of the appendedclaims.

What is claimed is:
 1. A medical apparatus for use with an endoscope,the apparatus comprising: an end cap adapted to fit on the distal end ofan endoscope, wherein the end cap comprises a through bore for receivingthe distal end of the endoscope, and wherein the end cap has an outersurface adapted to guide a medical instrument.
 2. The medical apparatusof claim 1 wherein the end cap outer surface is adapted to guide amedical instrument relative to an axis of the endoscope.
 3. The medicalapparatus of claim 1 wherein the end cap outer surface comprises a slot.4. The medical apparatus of claim 1 wherein the end cap comprises aninclined surface feature for guiding a medical instrument relative to anaxis of the endoscope.
 5. The medical apparatus of claim 1 wherein theendcap has an outer surface feature having an angle of inclination withrespect to the longitudinal axis of the through bore of the endcap. 6.The medical apparatus of claim 5 wherein the angle of inclination isbetween about 10 degrees and about 30 degrees.
 7. The medical apparatusof claim 1 wherein the endcap comprises an insert for releasablyengaging the distal end of an endoscope.
 8. A medical apparatus for usewith an endoscope comprising: an endcap adapted to releasably engage thedistal end of an endoscope; and a flexible track extending proximallyfrom the endcap.
 9. The medical apparatus of claim 8 wherein theflexible track has a length of at least 50 cm.
 10. The medical apparatusof claim 8 wherein the flexible track has a length of at least 100 cm.11. The medical apparatus of claim 8 wherein the flexible track haslength substantially equal to or greater than the insertion length of anendoscope with which it is associated.
 12. The medical apparatus ofclaim 8 wherein the flexible track has a distal end joined to theendcap, and a proximal end adapted to be supported in fixed relationshipto a proximal portion of an endoscope.